Expanding Adhesives? 1

[tffy]

Hi everyone. I'm trying to fill in a post-casting gap between two materials of differing CTEs, in a closed environment.

I'm looking for some sort of a slow cure (about 4 hours at appoximately 200 degrees F) adhesive that expands upon cure. Do any such materials exist out there?

Thanks a bunch!

Just to make sure, the adhesive does not need to be heat-activated, it's just it will have to cure in a high-temperature environment. Ideally it'd be a two-part mix adhesive.

 

[unclesyd]

I have heard that some of anaerobic adhesives expand ever so slightly on curing, no details.

I would give the following company a call and discuss your requirements. They have been pretty good either with their products or referred me to another product.

http://www.masterbond.com/index.html

 

[Demon3]

Yes it is possible.

Some cylcic monomers expand when cured. There are some epoxies that do, I know as I once worked with a man who was developing them for dental adhesives.

Probably the easiest way to get expansion during cure is through expandable microbeads that expand when heated. You can add these to a normal adhesive formulation. The best known in Expancel from Akzo Nobel, contact

http://www.expancel.com

for more information.

 

[tffy]

Thanks all... Will research this further, and see if I come up with anything on your leads.

 

[PanelGuy]

Micro beads are also available in McMaster Carr and most boat dealers from West Systems Epoxies.

Absolutely the right thing, as the adhesiveexotherms, the airin the beads expands a little...It is generally the ingredient in an expanding non-foaming type material.

 

[Demon3]

Sounds interesting panel guy. I haven't seen that type of bead. The beads I mentioned are an alkane (like gasoline) microencapsulated in a thin polymer shell. When heated the liquid boils and the beads expand to 40x their original volume. You can get different beads depending what expansion temperature you want.